I'm betting the same, redesigned B58 with a manual would be quicker than a VR30 with a manual. It would also be a riot to drive. Most people will probably dump them well before 100k anyway, leaving the later life issues to be somebody else's problem.Supra's closed-deck B58 when coupled with a 6-speed I think will be quicker than the Z's VR30 manual, that's a strong motor and underrated as BMW always does. Reliability will be no match to the VR30 though as we all know about BMW mills. My N54 TT 5 series is poking along at 62k miles and has been mostly reliable, couple of injectors replaced that's all. But I won't trust it above 150k miles, such are BMWs in general.
Reliability on my N54 started going downhill around 70k miles. At 150k miles the cost of parts/labor to fix what really needs to be addressed (not including things like brakes, tires or anything suspension related) pretty much exceeds the value of the car. Once I start adding in the cost of future upgrades such as suspension, LSD, and fueling I realize that I must be insane to continue down this path, but when you already have $XX,XXX amount into it where do you draw the line?